Electrical controller for conveying systems



Aug. 20, 1929. v R. G. LOCKETT 1,725,202

ELECTRICAL-CONTROLLER FOR CONVEYING SYSTEMS Filed Feb. 23, 1926 2 Sheets-Sheet l INVENTOR.

ATTORNEY 1929- R. e. LOCKETT 1,725,202

ELECTRICAL CONTROLLER FOR CONVEYING SYSTEMS Filed Feb. 23, 1925 2 Sheets-Sheet 2 INT/ENTOR.

W s. M BY ATTORNEY Patented Aug. 20, 1929.,

UNITEDSTATES PATENT OFFICE.

RALPH e. Locxn'rr, or MILWAUKEE, WISCONSIN, ASSIGNOR, BY mnsnn ASSIGN- MENTS, TO CUTLER-HAMMER INC A CORPORATION OF DELAWARE.

ELECTRICAL CONTROLLER FOR CONVEYING SYSTEMS.

Application filed February 23, 1926. Serial No. 90,088.

This invention relates to electrical controllers for conveying systems and while not limited thereto. is articularly applicable to the control of pu verized fuel feeding devices for the furnaces of boilers and the like.

An object of the invention is to provide a fuel feeding system for boiler furnaces and the like wherein the amount of fuel supplied is controlled automatically in accordance with .the demand upon the boiler.

' Another object is to provide for automatically varying insubstantially equal increments or decrements the quantity of fuel supplied to the furnace, throughout the total range of variation in the fuel supply.

Another object is to provide a plurality of fuel feeding devices for the boiler fur-.

uacewith means for automatically varying 2 the number of such deV1C6S-1I1 operation at a given t1me.-

of motor driven devices of the above character, with means for insuring operation of 5 certain or all of said devices, in accordance with the demand upon the boiler.

Another object is to provide means for automatically varying the speed of the driving motor uponvariation 'in the number of fuel feeding devices connected therewith, to thereby rovide forgradual variation in the rate of uel supply.

Other objects and advantages of the inyention will hereinafter appear.. The accompanying drawing illustrates an embodiment of the invention which will now be described, it bein understood that the invention is suscepti le of embodiment in I other forms without departing from the spirit and scope of myinvention as defined in the ap ended claims.

In the rawing, V g Figure 1 is a schematic and dia rammatic view' of'a device constructed an arranged in accordance with my invention, and

Fig. 2 is an across-the-line diagram of the circuit connections illustrated in Fig. 1. Referring to Fig. 1, the numerals 5, 6 and 7 designate abattery of fuel-feeding devices adapted to supply pulverized fuel to, a single boiler furnace '(not shown). Said devices may be of a well known construction, and as shown each comprises a receptacle (1 for pulverized fuel, a screw conveyor '6 driven preferably through worm gearing a for. carrying the fuel to a blower d, from which it is discharged through nozzlee into the furnace. Said devices are respectively provided with electromagnetic clutches 8, 9 and 10- which are operable in the manner hereinafter described to connect the same to or, disconnect the same from a rotatable shaft 11 driven by a motor, the armature of which is indicated at 12, suitable .bevel gearing being provided as shown. Said motor is adapted to have its speed increased or decreased by variation of the amount of resistance included in circuit with the shunt field f in the manner hereinafter described. The motor is supplied with energy from a source of direct current, the supply lines being indi-- cated at L L whereas the armature 12 and field f are permanently connected at oneside thereof to line L? by conductor 13.

v ;The motor starter may-be of a standard Another object is to providea plurality form, and as shown the same comprises an electro-responsive main switch .14, an accelerating relay 16.

A remote control push-button" station is normally open start button 17 and 3. normally closed stop button 18. Thus upon clorelay 15, and a vibrating field' provided, the same comprising a sure of start button 17 an energizing circuit" I a is provided for the winding of main switch 14, said circuit extending from line L, by conductor 19 through the contacts of said button 17, by conductors 20 and 21 through the normally closed contacts ofbutton'18, b

conductor 22 through the winding ofswitcld 14, and b conductor 23 to line L. Switch 14 upon cl osure thereof provides a maintaining circuit for its winding, said circuit'extending from line ,L by conductor 24 through auxiliary contacts 25, by conductors 26 and 21 through the contacts of button 18,.

and thence to line L as previously traced.

Main switch 14 upon closure provides a circuit for the armature ofth'e motor, said circuit extending from line. L through the pole contacts 14 of said switch 14, by conductor 27 through the coils 28 and- 29 of relay 15 in series, thence by conductor 30 through the lockout coil 31 of relay 16, by

conductor: 32 through series coil 33 of said relay, by conductor 34- through' starting re- 'sistance 35, by conductor. 36"throu h, the

armature '12, and by conductor 13 to hne L".

. torque and slow speed operatlon of the The energizing circuit for the shunt coil 37 of relay 16 may be traced from line L by conductor 24 through auxiliary contacts 25 of switch 14, by conductors 26 and 38 through said coil, and by conductor 39 to line L Due to energization of coils 28 and 29 of relay 15 in the manner aforedescribed the normally open contacts 40 of said relay motor. After a predetermined period, during which the initial inrush of current to the motor subsides, the coils 33 and 37 become predominant, thus effecting closure of contacts 43 of relay 16, which short-circuits.

coil 29 of relay 15, starting resistance 35) and coils 31 and 33 of relay 16. Said lastmentioned circuit may be traced from line L through coil'28, by conductor 44 through contacts 43, and by conductors 45 and '36 through armature 12 to line L Q Contacts 40 of relay "15 will thereupon open, thereby "subjecting the circuit of shunt field f to control by a rheostat R. The circuit thus pro-,

vided may be traced from line L through mam switch 14, by conductors 27, 46 and 47,

7 through acontact segment 48 and contact arm 49 of the rheostat to a point in the resistance sections 1 1' or r corresponding with the angular position of arm 49, thence through the resistance by conductor 50'to conductor 42, and through field f to line L \Vith contact arm 49 positioned as illustrated in the drawing, obviously none of the resistance will be included in the field cir-, cuit, and it'may be assumed that under such conditions the motor is adapted to operate ata speed of 700 R. .P. M.; whereas with maximum resistance in the field circuit the motor is adapted to operateat a speed of 2100 R. P. M. Rheostat R is also provided -with a plurality .of auxiliary contact segments 51, 52 and 53.adapted to be engaged by contact arm54 for control of relays R and R in the manner now to be described.

. Qontact arms-49 and 54 are formed integi 48, through contact arms 49 and 54, to segment 51, by conductor ,55 through'normally closed auxiliary contacts 56 on relay R, by

conductors 57 and 58 through the winding of relay R and by conductors59 and 60 to through the le line; L Relay R thereupon closes and t-hand contacts to thereof completes an energizing circuit for the winding of electromagnetic clutch 9. Said circuit extends from line L to conductor 46 as previously traced by conductor 61 through the left-hand contracts 10' ofrelay R", by conductor 62 through the winding of clutch 9 and by conductors 63, 64 and 65 to line L Clutch 9 thereupon acts to connect the fuelfeeding device 6, through suitable gearing, to the drive shaft 11 of the motor.

In the particular installation hereindisclosed each of the fuel feeding devices 5, 6 and 7 is adapted to supply pulverized fuel at rates ranging from 8% pounds per minute, When the motor is operating at the minimum speed of 700 R. P. M., to 25 pounds per minute, when the motor is operating at the maximum speed of 2100 R. P. M. I have therefore provided cooperating clutch control and speed control'means'whereby the rate of fuel supply to the. boiler furnace may be varied from 8 pounds per minute to 75 pounds per minute. Moreover, I have provlded means whereby the rate of fuel supply is automatically varied in accordance with the demand upon the boiler. Said 'means may comprise a lever 66 pivoted at 67 and oper- 'able by means of anexpansible'member 68 subjected, as by pipe69, to the steam pressure of the boiler. Pivotally connected to one end of lever 66 is a rod 70 carrying a pair of'spaced pistons or blocksf71 and 72 adapted to slide within a passageway 73, said. blocks acting, in the position illustrated, to

jointly close passages 74 and 75 leading to the lower and upper sides, respectively, of a piston 76 operating in a cylinder 7 7 Leading into the passageway 73 intermediate said blocks 71 and 72 is a conduit 78 connected with any suitable source of'fiuid under substantially constant] pressure. Thus assuniing movement of blocks 71 and 72 upwardly by the means aforedescribed fluid-under pressure will pass through conduit'78, passageway 73 and conduit 75 to the chamber above piston 76,- thus' tending to force the latter downwardly; whereas obviously the chamber beneath piston 76 .will be in communication. through passage 74 and chamber 79, with exhaust or outlet 80. Such down ward movement of piston-76 and the attached rod 81 will, through suitable 'rack and pinion gearing 82, 83, effect counterclockwise movement of contact arms 49 and 54 of the rheostat. Similarly, upon downward movement of blocks 71 and 72, conduit 78 will be thrown into communication with the chamber beneath piston 76, through passageway 73- and conduit 74, whereas the chamber above said piston will communicate with outlet 84, through chamber 85 and conduit 75.' The blocks 71 and 72 "are adapted to move upwardly under the action of the weight 86 carried by lever 66 when the amount of steam generated is insufiicient to meet thedemand 39 I upon the boiler, and as af oredescribed the 49 and 54 thus decreasing the rate of fuel supply. p

Referring again to the rheostat R, it will be noted that upon counterclockwise movement of arm 54 the latter is adapted to engage segment 52 just prior to disengagement thereof from segment 51, so that relay R is energized and closed to bring in clutches 8 and 10 substantially simultaneously with deenergization of relay R which opens to drop out clutch 9. At the same time contact arm 49 will be in engagement with contact 87 of the rheostat, so that upon closure of relay R a portion of the resistance previously included in the circuit of field 7 will be short circuited to temporarily reduce the speed of the motor. Said short-circuit may be traced from contact 87 by conductor 88 through the left-hand contacts 2 of relay R ,'by conductor 89 to an adjustable contactor 90.. The aforedescribed short-circuit will be effective during continued closure of relay R whereas upon continued movement of arms 49 and 54 in a counterclockwise direction the resistance in section r? is gradually included in the field circuit to increase the motor speed,

with consequent increase in the amount of fuel supplied by devices 5 and 7, until arm 49' is in engagement with contact 91, at which time arm 54 will be in engagement with segment 53, thus providing an energizing circuit for the winding of relay R shunting the auxiliary contacts 56 of relay R which contacts are then inopen position.

Said energizing circuit, which extends by conductors 92 and 58 through the winding of relay R will be obvious. Upon reclosure of relay R the winding of clutch 9 will be energized,the energizing circuit being completed "through closure ofthe left-hand contacts w of said relay, as 'aforedescribed.

Closure of the right-hand contacts 02 of said said devices jointly will be substantially equal to or slightly in excess of the maximum rate' of supply when devices 5 and? only were in operation. Thereafter upon continued movement of arm 49 in a counterclockwise direction the field f is weakened by gradual inclusion of the steps of resistance in section r until the motor is operating at the maximum speed (2100 R. P. 1V1.) with all of the devices 5, 6 and 7 connected thereto.

By suitably arranging and calibratingthe resistance sections 1 ,1 and 1' and the segments 51, 52 and 53 for varying the number of fuel-feeding devices connected to the motor drive I am enabled to vary'the rate of 'fuel supply through the wide range aforeindicated; whereas the arrangement is preferably such that a uniform change in the rate of fuel supply is effected .upon each unit of travel ofthe rheostat arms 49 and 54. Ohviously upon a decrease in the demand upon the boiler the control elements are operated in the reverse direction to automatically and proportionately decrease the rate of fuel s p y-- p Operation of the electrical control elements'will' now be described in connection with the line diagram 'of Fig. 2. Thus'assuming momentary closure of push-button switch 17 an energizing circuit for thewvinding of main switch 14 is provided, said circuit extending from line L through switch 9 17 and normally closed stop push-button switch 18 through said winding to line L a parallel energizing circuit for winding 37 of relay 16 being also provided. Upon closure of switch 14 a circuit for armature 12 of the motor is completed, said circuit extending from line L through the pole contacts 14 of switch 14, thence in series through windings 28 and 29 of relay 15, windings 31 and energization of winding 31 is decreased, whereupon windings 33 and 37 cooperate in relay effects short-circuitlng of a portion of i a well known manner to effect closure of contacts 43 ofr'elay 16, thereby short-circuiting winding 29 of relay 15 and windings 31 and 33 of relay 16; contacts 43 being held in closed position-due to continued energization of winding 37.. Upon 'short-circuiting of winding 29 the winding 28 becomes incapable of holding relay 15 in closed position, and

upon'opening of the contacts 40 thereof the amount of resistance included in circuit with field f is dependent upon the position of rheostat arm 49. Thus assuming a minimum demand upon the boiler, arm.49 will be in the position illustrated wherein the motor is subjected to full field strength; and it-may be mumed that under such conditions the motor will operate at a speed of 700 R. P. M. Moreover, under these conditions the winding of relay R will be energized by a circuit extending from line L through the main switch contacts 14*, thence to segment 48, rheostat arm 54, to segment 51,'and through normally closed auxiliary contacts 56 of relay R through said winding to line L Upon closure of relaylt theleft-hand contacts w thereof complete an energizing circuit for the winding of clutch 9, said circuit being obvious. The fuel feeling device is therefore driven by the motor, and at the motor speed aforementioned said device may be assumed to be supplying fuel at the rate of 8 pounds per minute. If the demand upon the boiler increases the-arm 49 is gradually moved to the left to include steps of resistance section 1' in circuit with field f. until the contact 87 is reached, at which point the motor may be assumeed. to be operating at a speed of 1750 R. P. M., with device 6 supply ing'fuel at the rate of "about'21 pounds per minute. 1

If the demand upon the boiler increases further arms 49 and 54 will continue to move gradually to a corresponding degree, whereas prior to inclusion of any of the steps of resistance in section 1' by arm 49, arm 54 will move into engagement with segment 52 to complete an energizing circuit for the winding of relay R whereas arm 54 will be simultaneously moved out .of engagement with segment 51, thus interrupting the energizing circuit of relay R and the drive of device 6.

Glosure of relay B through its right-hand contacts ycompletes an energizing circuit for the clutch windings 8 and 10 in parallel,

' thereby connecting fuel feeding devices 5 and 7 to the motor drive. Also upon closure of the left-hand contacts 2 of relay R a portion of the resistance section 1 will be short-circuited, the strength of field 7 being in this mannersufliciently increased to reduce the motor speed toabout 925 R. P. M., at which speed of the motor the devices 5 and 7 will jointly supply fuel at the rate'of about 22 pounds per minute.

Upon continued movement of arm 49 the:

steps of resistance section 1'? will be gradually iincluded until the contact 91 is reached,at which point the motor seed may be assumed to be about 1600 HP. at which speed of the motor the devices 5 and 7 .will jointly supply fuel at the rate of 38 pounds per minute. Upon continued movement of arms 54 and 49 the former will come into engagement with segment 53 to provide an energizing circuit for the winding of relay R independently of auxiliary contacts 56 of relay R whereas relay R in closing v short-circuits a portion of resistance section 1' through the right-hand contacts w thereof. Thefield f will thus be again tempo-.-

rarily strengthened to provide amotor speed of about-1100 R. P. M. with all of the devices 5, 6 and 7 connected thereto, and

jointly supplyingfuel at the rate of about" 39 pounds per minute Movement of arm 49 may continue until all of the resistance section 1- as well as the non-short-circuited portions of resistance sections 1' and 7' are will then be jointly supplying fuel at the rate of 75 pounds per minute. If necessary or desirable a suitable stop may be provided for limiting travel of the arms. 49 and 54 in a counterclockwise direction. The manner of operation of thefsystem in a reverse direction to decrease the rate of fuel supply due to a decrease in the demand upon-the boiler is believed to be obvious without further description. 7

It will be noted that when conditions are. such that the fuel demand may be supplied v by a single feeder the fuel is, supplied through the nozzle of the middle device 6,

Whereas when two feeders are required the.

fuel is supplied through the nozzles of the end feeders 5 and 7. In this manner better combustion conditions in the furnace are ob-' tained; but it is to be understood that the mode of operation of the system in this respect may be modified if desired.

While I have shown the present device as applied to the control of the fuel supply to a single boiler furnace, it is to be understood that the same is equally applicable to the control of a plurality of boilers ada ted to jointly supply a common demand. 11 such an installation certain ofthe boiler fuel feeding control devices would be set to provide a constant rate of fuel supply, whereas other of such deviceswould be operative asherein described to accommodate variations in the steam demand upon the boilers jointly. Moreover, the arrangement would be such that the boiler fuel feeding controllers could alternatively be connected for variation of.

the fuel supply, whereby difierent boilers would be adapted to accommodate the variable steam demand upon the boilers jointly.

What I claim and desire to secure by Letters Patent is:

1. Ina controller for fuel feeding devices, the combination with a plurality of fuel feeding elements, of common driving means for said elements, means for automatically varying the speed of said driving means, and means for automatically varying the number of said elements connected with said driving means in accordance,.with the fuel demand of the service being supplied creasing or decreasing the number of fuel feeding'elements connected with said motor, and means for gradually varying the speed of said motor to thereby vary the amount of fuel supplied by said elements, said means including means for abruptly varying the speed of said motor upon an increase or decrease in the number of said elements connected therewith to thereby provide for gradual variation of the amount of fuel supplied by said elements throughout the total range of supply thereof. g

- 3. In a fuel feed controller for boiler furnaces, the combination with a plurality of fuel feeding elements, of a common driving motor there-for, means for sequentially increasing or decreasing the number of fuel feeding elements connected with said motor, means for gradually varying the speed of said motor to thereby vary the amount of fuel supplied by said elements, said means including means for abruptly ,varying the speed of said motor upon an increase or decrease in the numberof said elements connected therewith to thereby provide for gradual variation of the amount of fuel supplied by said elements throughout the total rangeof supply thereof, and means for subjecting said speed varying means to control in accordance withv pressure conditions in the boiler. 7

4. In a fuel feeding device, the combina tion with a plurality of fuel feeding elements, of a common drive for said elements, means for connecting one of said elements with said drive, means operable automati- -'cally in response to variations in the fuel demand forgradually varying the rate of operation ofsaid element, and means operable automatically for thereafter disconnecting said element from said drive and simultaneously connecting other of said elements with the latter.

connect said first mentioned element with said drive.

' 6. In a fuel feeding device, the combination with a plurality of fuel feeding elements, of a common driving motor for said elements, means for connecting one of said elements with said motor, means for automatically varying the speed of said motor through a given range to thereby vary the amount of fuel supplied by said element, means for thereafter automatically disconnecting said element from said motor and simultaneously connecting other of said elements with the latter, and means for insuring a predetermined decrease in the speed of said motor upon connection of said lastmentioned elements therewith.

'7. In a fuel feeding device, the combination with a plurality of fuel feeding elements, of acommon driving motor for said elements, means for connecting one of said elements with said motor to be driven thereby, means for gradually increasing the speed I of said motor through a predetermined range to provide for increasing the amount of fuel supplied by said element, means for interrupting the operation of said element when a predetermined rate of supply thereof has been attained, and means for simultaneously connecting a plurality of the other of said elements with said motor to be driven thereby under conditions of temporarily reduced speed of the latter, whereby the initial rate of supply of said last-mentioned elements jointly is substantially equal to the aforementioned rate of supply of said first-mentioned element.

8. In a fuel feeding device, the combina- 4 tion with a plurality of fuel feeding elements,-of a common driving motor for sa d element's, means for connecting one of said elements with said motor to be driven thereby, means for gradually increasin the speed of said motor through a pre etermined range to provide for increasing the amount of fuel supplied by said element, means for interrupting the operation of said element whena predetermined rate of supply thereof has been attained, means for simultaneously connecting a plurality of the other of said elements with said motor to be driven thereby under conditions of temporarily reduced speed of the latter, whereby the 1n1t1al rate of supply of said last-mentioned elements jointly is substantially equal to the aforementioned rate of supply of sald first-mentioned element, means for gradually mcreasing the speed of said motor unt1l a predetermined rate of supply of said second-mentioned elements has been attained, and means for thereafter reconnecting said first-mentioned element under conditions of temporarily reduced speed of the motor, whereby the initial rate of supply of all of said elements jointly is substantially equal to the aforementioned rate of supply of said second-mentioned elements.

9. In a fuel feeding device, the combination with a plurality of fuel feeding elements, of a common driving motor for said elements, means for connecting one of sald elements with said motor to be driven thereby, means for gradually increasin the speed.

of said motor through" a pre etermined i is range'toincrease the amount of fuel sup-- plie'dby said element means for interrupt ing the operation of said element when a predetermined rate of supply thereof has een attained, means for simultaneously connecting a plurality of other of said elements with said motor to be driven thereby 'under conditions of temporarily reduced speed of the latter, whereby the. initial rate of supply of said last-mentioned elements jointly is substantially equal to the aforementioned rate of supply of' said first-mentioned element, means for gradually increas-.

ing the speed of said motor until a predetermined rate of supply of said second-mentioned elements has been attained, means for thereafter reconnecting said first mentioned element under conditions of tempo-- 'rarily reduced speed of the motor, whereby the initial rate of supply of all of said elements jointly is, substantially equal to the aforementioned rate of supply ofsaid second-mentioned elements, and means for gradually increasing the speed of said motor 1 until the maximum rate of supply of all of said elements jointly has been attained.

r10. In a controller for pulverized fuel feeding'systems for steam boilers, the combination with a plurality of devices for supelectromagnetic clutches for connecting said plying the fuel. under pneumatic pressure,

devices with a common driving motor, electromagnetic relays for controlling said clutches selectively, circuit 'commutating' means for controlling the operation of said .relays, and means responsive to boiler pressure conditions for controlllng the operation of said commutating means.

11. In a controller for pulverized fuel feeding systems for steam boilers, the combination with a plurality of devices for supplying'thefuel 'under pneumatic pressure,

. electromagnetic clutches for connecting said devices with a common driving motor elec-,

tromagnetic relays for controlling said clutches selectively, "circuit commutating means for controlling the operation of said relays, and means respgnsive 'to boiler conditions for controlling the operation of said. .commutating means, gsaid commutating means including means for automatically controlling operation of said clutches, circuit commutating meansfor controlling operat1on of said relays, said means including means for gradually varying the amount of nection of one or more of said elements to said motor,'and interlocking means between said relays and said commutating means to provide for abrupt variation in the amount of resistance incircuit with said field "upon 'variatlon 1n the-number of elements con nected to said motor.

13. In a'control system, in combination, a plurality of driven devices, common driving resistance in circuit with said field upon conmeans therefor, and means operable automatically to vary the number of said devices connected with said driving said second 'mentioned means including means to simultaneously vary the speed of said driving means.

means,

14. In a controlsystem, incombination,

'a common driving motor,a plurality of de-' vices to be jointly or severally connected therewith to'be driven thereby, and. means operable automa-tically for gradually varying the speed of said motor during connectiontof certain or all, of said devices therewith, said means being also operable auto;

Iiiatically'to abruptly vary the speed of said motor upon variation in the number of devices connected therewith. I In witness. whereof, I have hereunto subscribed my name.

RALPH- G. Loo E'rT. 

